1. Field of the Invention
This invention relates to vinylidene chloride (VDC) interpolymers. In one aspect, the invention relates to a blend of a VDC interpolymer and poly(butylene succinate) (PBS) while in another aspect, the invention relates to improved barrier packaging.
2. Description of the Related Art
Vinylidene chloride interpolymers are well known in the art. VDC interpolymers are known for their high barrier to mass transport of atmospheric gases and water vapor. VDC interpolymers are frequently fabricated into mono- and multilayer blown or cast films. However, due to the proximity of the glass transition temperature (Tg) of VDC interpolymer to room temperature (23° C.), these films are susceptible to brittle failure. As such, the improvement in the tear resistance of film made from VDC interpolymer without a significant deterioration in the barrier properties, e.g., oxygen transmission rate (OTR), of the film is of continuing interest to the packaging industry.
U.S. Pat. No. 4,725,651 teaches a polymeric, miscible blend comprising 1 to 80 weight percent (wt %) VDC interpolymer and 20 to 99 wt % of a thermoplastic copolyester resin. The copolyester reins are made from more than one polyhydric alcohol and/or more than one dibasic acid. While the blends of this teaching exhibit physical properties superior to those expected by the rule of mixtures, neither the affinity of the copolyester resin for the VDC interpolymer nor the tear resistance of a film made from the blend is completely satisfactory.